overheating

[fenrisx]

A few days ago my 4Runner began to overheat at stoplights, and just been running hot in general. The coolant was low, and looked like some was leaking from the radiator hose going to the engine. We pulled the hose off, and then scraped off all the corrosion on the inlet. Put some more coolant in, and thought everything was good to go. Well, it did it again yesterday. The coolant level is fine still, so it isn't that.

Another thing... since this has started the 4Runner will make a weird noise under acceleration from time to time. Both during this, and then sometimes when it isn't hot. I can't really explain the noise. To my ears it sounds somewhat metallic. It reminds me, in a way, of a chain spinning off a gear.

Any idea on the overheating, and the noise? Maybe the waterpump is going? I have no clue.

[CJM]

You need to pressure test it to see where your leak is coming from if you have one.

Did you check the oil, is it milky. Milky oil like a milkshake means your headgaskets gone, exhaust will smell sweet too.

Could be the waterpump, heater core too.

[fenrisx]

I don't think there is a leak. We filled it several days ago, and the levels haven't changed since then.

The oil isn't milky.. We checked that the day we filled it up with coolant.

I'm leaning towards the water pump due to the noise I'm hearing. Someone said, from what I told them, it sounds like the water pump might be seizing up.

[fustercluck]

I'm betting water pump. The first thing I do though is boil the thermostat to make sure it is functioning properly. The next suspect is the water pump. Wouldn't expect the radiator to go yet unless you use tap water rather than filtered or distilled water. Is the grinding sound coming from the front of the motor in the center? You might have a bad fan clutch...

[fenrisx]

It's hard to tell where the noise is coming from. By the time it happens, and I roll down the window to listen, it doesn't do it again until I'm not expecting it. I want to say it's coming from the right side where the pump is, but honestly it could just as well be more toward the center of the engine.

[CJM]

Boil the thermostat and see if it works right, check the hoses-they should have some give but still be stiff, with truck off grab the fan and move it around, if it has play clutch is bad, then finally waterpump is the last thing.

[MTL_4runner]

If you coolant is down and you hear noises, your WP may already be weeping. Tke is from someone who knows, replace it now if you suspect it in the least and replace the thermostat on principle as well. You may want to have the cooling system pressure tested to ensure it can hold pressure and doesn't have any visible leaks.

If the WP goes then you'll be moving on to an "overheating" thread like this:
http://www.ultimateyota.com/index.php?option=com_smf&Itemid=26&topic=2241.0

[fenrisx]

The WP isn't weeping or anything... I think the sound I'm hearing is due to the engine being so hot the oil isn't lubricating properly, and just other things happening due to the heat, just guessing. I have a hard time explaining the sound.. but it reminds me of a chain being drug across metal, link after link, just a little deeper in sound.

---

I just made a nice journey from MN to GA and back. On the trip down the truck started overheating once in Illinois when we waited in line at Taco Bell. Once we started moving it was fine though. Then when in Georgia it did this about 3 times. The third time I made it to AutoZone just before it reached red. Stayed AutoZone about 25 minutes so it could cool. Bought a thermostat while I was in there. I turned the key to ACC to see where the temp was before starting it, and then when I started it up it idled really rough for about 20 seconds.

From there I headed to my brothers house. We changed out the thermostat, radiator cap, and coolant. As you could guess... the problem persisted the next day.

Drove back to MN and had it over heat every time we'd go through a drive through, or sit for a few minutes.

So yesterday when I got back I went to AutoZone and got a fan clutch. I put that on, and changed the oil while I was at it. So far so good. I let it sit and run or a while..drove to AutoZone in rush hour traffic to dispose of the old oil..came back and let it run some more. It didn't over heat any, so I'm hoping it's good now.

[fenrisx]

I remember a long thread about proper types of coolant, but I couldn't find it. I wanted to run Toyota SLL through it, but didn't have the $ to spend over twice as much as what I ended up getting. I bought Prestone Dex Cool.. orange stuff. Hopefully it's ok.

I plan on having them flush it out and replace with SLL at the dealership when I have the belts and waterpump replaced in a about a month.

[4x4mike]

I use the red coolant from the dealer. I just did my system. Basically I drained the system from the radiator and then topped it off with distilled water. Drove it around for a day, drained again and topped off. I did this for a couple of days before filling it up with a 50/50 mix. FWIW I would only use a termostat and radiator cap from the dealer. The price isn't much different for what you get. I have always had problems with Stant caps and cheap termostats.

If you're going to have someone pull everything apart for the water pump you should have the timing belt done unless that's what you mean by belts. The accessory belts are easy to change yourself but again if it's all off it's easiest to replace all at once.

[fenrisx]

Speaking of which... that's another reason I'm going to have the dealer replace with their coolant.. We just used water from the hose, not distilled.

I still have the OEM radiator cap, I'll probably put it back on. Then I'll just keep the Stant in the toolbox just in case I ever need one.

I would have went OEM on the t-stat, but it was twice as much. I was on a tight budget... didn't really have the cash to spend on the clutch... that's why I just went to AutoZone. You can definitely tell the difference between the OEM and AutoZone thermostat. The OEM is much beefier looking.

I did mean the timing belt when I said belts. I thought about doing the accessory belts myself, but since I was going to have the dealer throw a new timing belt on next month I figured I'd just wait until then and let them do it.

[CJM]

I highly doubt the type of coolant is issue here.

Get a compression and leak down test performed. Low compression means the head gaskets bad. The more it overheats the more chance your gonna warp the heads or cause the block to crack.

[DHC6twinotter]

FWIW I would only use a termostat and radiator cap from the dealer. The price isn't much different for what you get. I have always had problems with Stant caps and cheap termostats.


X2. Every radiator cap I have ever purchased from the parts store has had issues. OEM is the only way I will go.

[fenrisx]

I highly doubt the type of coolant is issue here.

Get a compression and leak down test performed. Low compression means the head gaskets bad. The more it overheats the more chance your gonna warp the heads or cause the block to crack.


I just mean I hope the type of coolant is okay for the 4Runner. There was some long thread about coolant types that I remember seeing a few weeks ago basically saying it's not good to just use any coolant..

The truck seems good now after I replaced the clutch fan. We were out all day today with no issues. Left it running when parked with no issues.

I'm going to swap out the radiator cap tomorrow with the original one..

If I have any more issues I'll have a compression test done.

[CJM]

Is the toy coolant better? Maybe yes, maybe no. Honestly most coolants are about equal, I ran prestone green for ages with no problems at all.

Imho coolant is only junk when you leave it in there for 5+ years and it turns to sludge.